This invention relates to improvements in the electrical connector assemblies for submersible electric motors, such as disclosed in U.S. Pat. Nos. 3,997,232 and 4,053,196 which issued to the Assignee of the present invention. In such submersible electrical motors, for example, of the type used in combination with a deep well water pump as disclosed in U.S. Pat. No. 3,250,927, it is common for the motor to be submerged within the well water at a substantial depth. Electrical lead wires, commonly referred to as a "drop cable" extend from an external power source downwardly through the well casing to the electric motor. The motor may be provided with a power supply cord of predetermined length, and the drop cable is connected to the power supply cord by means of a splice or a molded-on cable connector, for example, of the type disclosed in U.S. Pat. No. 2,958,842. It is also common to provide the "drop cable" with a plug-type connector which is molded onto the lower end of the drop cable and plugs into a mating socket member supported within the submersible motor housing. For example, U.S. Pat. Nos. 3,059,210; 3,248,582; 3,294,993; 3,308,316; 3,350,587 and 3,777,194 disclose various forms of electrical plug-type connectors for a submersible electric motor.
As set forth in U.S. Pat. Nos. 3,997,232 and 4,053,196, it has been found highly desirable to eliminate the need for forming a splice with electrical power supply lead wires or a "drop cable" and to simplify the connection of the lead wires to the motor so that it is unnecessary for a motor and/or a motor-pump manufacturer to supply a "drop cable" having a molded-on electrical plug member which mates with the socket member within the motor. Furthermore, the elimination of the plug-type connector eliminates the need for producing and supplying "drop cables" of various lengths corresponding to the depth of the motor-pump unit below the ground surface.
In view of the fact that electric motors submerged within a current conducting liquid such as well water are subjected to electrical grounding, it is desirble to protect the motor from a power or voltage surge, for example, as caused by lightning hitting the electrical power supply lines or "drop cable". One form of lightning arrestor for a submersible electrical motor, is disclosed in U.S. Pat. No. 3,849,704. This arrestor incorporates an electrode within a gas generating, arc extinguishing material contained within a closed casing retained within the motor housing. Another form of lightning arrestor of the type used in connection with the present invention, is disclosed in above U.S. Pat. Nos. 3,997,232 and 4,053,196.